mca_drv.c

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/*
 * File:    mca_drv.c
 * Purpose: Generic MCA handling layer
 *
 * Copyright (C) 2004 FUJITSU LIMITED
 * Copyright (C) 2004 Hidetoshi Seto <[email protected]>
 * Copyright (C) 2005 Silicon Graphics, Inc
 * Copyright (C) 2005 Keith Owens <[email protected]>
 * Copyright (C) 2006 Russ Anderson <[email protected]>
 */
#include <linux/types.h>
#include <linux/init.h>
#include <linux/sched.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/kallsyms.h>
#include <linux/bootmem.h>
#include <linux/acpi.h>
#include <linux/timer.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/smp.h>
#include <linux/workqueue.h>
#include <linux/mm.h>
#include <linux/slab.h>

#include <asm/delay.h>
#include <asm/machvec.h>
#include <asm/page.h>
#include <asm/ptrace.h>
#include <asm/sal.h>
#include <asm/mca.h>

#include <asm/irq.h>
#include <asm/hw_irq.h>

#include "mca_drv.h"

/* max size of SAL error record (default) */
static int sal_rec_max = 10000;

/* from mca_drv_asm.S */
extern void *mca_handler_bhhook(void);

static DEFINE_SPINLOCK(mca_bh_lock);

typedef enum {
    MCA_IS_LOCAL  = 0,
    MCA_IS_GLOBAL = 1
} mca_type_t;

#define MAX_PAGE_ISOLATE 1024

static struct page *page_isolate[MAX_PAGE_ISOLATE];
static int num_page_isolate = 0;

typedef enum {
    ISOLATE_NG,
    ISOLATE_OK,
    ISOLATE_NONE
} isolate_status_t;

typedef enum {
    MCA_NOT_RECOVERED = 0,
    MCA_RECOVERED     = 1
} recovery_status_t;

/*
 *  This pool keeps pointers to the section part of SAL error record
 */
static struct {
    slidx_list_t *buffer; /* section pointer list pool */
    int      cur_idx; /* Current index of section pointer list pool */
    int      max_idx; /* Maximum index of section pointer list pool */
} slidx_pool;

static int
fatal_mca(const char *fmt, ...)
{
    va_list args;
    char buf[256];

    va_start(args, fmt);
    vsnprintf(buf, sizeof(buf), fmt, args);
    va_end(args);
    ia64_mca_printk(KERN_ALERT "MCA: %s\n", buf);

    return MCA_NOT_RECOVERED;
}

static int
mca_recovered(const char *fmt, ...)
{
    va_list args;
    char buf[256];

    va_start(args, fmt);
    vsnprintf(buf, sizeof(buf), fmt, args);
    va_end(args);
    ia64_mca_printk(KERN_INFO "MCA: %s\n", buf);

    return MCA_RECOVERED;
}

static isolate_status_t
mca_page_isolate(unsigned long paddr)
{
    int i;
    struct page *p;

    /* whether physical address is valid or not */
    if (!ia64_phys_addr_valid(paddr))
        return ISOLATE_NONE;

    if (!pfn_valid(paddr >> PAGE_SHIFT))
        return ISOLATE_NONE;

    /* convert physical address to physical page number */
    p = pfn_to_page(paddr>>PAGE_SHIFT);

    /* check whether a page number have been already registered or not */
    for (i = 0; i < num_page_isolate; i++)
        if (page_isolate[i] == p)
            return ISOLATE_OK; /* already listed */

    /* limitation check */
    if (num_page_isolate == MAX_PAGE_ISOLATE)
        return ISOLATE_NG;

    /* kick pages having attribute 'SLAB' or 'Reserved' */
    if (PageSlab(p) || PageReserved(p))
        return ISOLATE_NG;

    /* add attribute 'Reserved' and register the page */
    get_page(p);
    SetPageReserved(p);
    page_isolate[num_page_isolate++] = p;

    return ISOLATE_OK;
}

void
mca_handler_bh(unsigned long paddr, void *iip, unsigned long ipsr)
{
    ia64_mlogbuf_dump();
    printk(KERN_ERR "OS_MCA: process [cpu %d, pid: %d, uid: %d, "
        "iip: %p, psr: 0x%lx,paddr: 0x%lx](%s) encounters MCA.\n",
           raw_smp_processor_id(), current->pid,
        from_kuid(&init_user_ns, current_uid()),
        iip, ipsr, paddr, current->comm);

    spin_lock(&mca_bh_lock);
    switch (mca_page_isolate(paddr)) {
    case ISOLATE_OK:
        printk(KERN_DEBUG "Page isolation: ( %lx ) success.\n", paddr);
        break;
    case ISOLATE_NG:
        printk(KERN_CRIT "Page isolation: ( %lx ) failure.\n", paddr);
        break;
    default:
        break;
    }
    spin_unlock(&mca_bh_lock);

    /* This process is about to be killed itself */
    do_exit(SIGKILL);
}

static void
mca_make_peidx(sal_log_processor_info_t *slpi, peidx_table_t *peidx)
{
    /*
     * calculate the start address of
     *   "struct cpuid_info" and "sal_processor_static_info_t".
     */
    u64 total_check_num = slpi->valid.num_cache_check
                + slpi->valid.num_tlb_check
                + slpi->valid.num_bus_check
                + slpi->valid.num_reg_file_check
                + slpi->valid.num_ms_check;
    u64 head_size = sizeof(sal_log_mod_error_info_t) * total_check_num
            + sizeof(sal_log_processor_info_t);
    u64 mid_size  = slpi->valid.cpuid_info * sizeof(struct sal_cpuid_info);

    peidx_head(peidx)   = slpi;
    peidx_mid(peidx)    = (struct sal_cpuid_info *)
        (slpi->valid.cpuid_info ? ((char*)slpi + head_size) : NULL);
    peidx_bottom(peidx) = (sal_processor_static_info_t *)
        (slpi->valid.psi_static_struct ?
            ((char*)slpi + head_size + mid_size) : NULL);
}

#define LOG_INDEX_ADD_SECT_PTR(sect, ptr) \
    {slidx_list_t *hl = &slidx_pool.buffer[slidx_pool.cur_idx]; \
    hl->hdr = ptr; \
    list_add(&hl->list, &(sect)); \
    slidx_pool.cur_idx = (slidx_pool.cur_idx + 1)%slidx_pool.max_idx; }

static int
mca_make_slidx(void *buffer, slidx_table_t *slidx)
{
    int platform_err = 0;
    int record_len = ((sal_log_record_header_t*)buffer)->len;
    u32 ercd_pos;
    int sects;
    sal_log_section_hdr_t *sp;

    /*
     * Initialize index referring current record
     */
    INIT_LIST_HEAD(&(slidx->proc_err));
    INIT_LIST_HEAD(&(slidx->mem_dev_err));
    INIT_LIST_HEAD(&(slidx->sel_dev_err));
    INIT_LIST_HEAD(&(slidx->pci_bus_err));
    INIT_LIST_HEAD(&(slidx->smbios_dev_err));
    INIT_LIST_HEAD(&(slidx->pci_comp_err));
    INIT_LIST_HEAD(&(slidx->plat_specific_err));
    INIT_LIST_HEAD(&(slidx->host_ctlr_err));
    INIT_LIST_HEAD(&(slidx->plat_bus_err));
    INIT_LIST_HEAD(&(slidx->unsupported));

    /*
     * Extract a Record Header
     */
    slidx->header = buffer;

    /*
     * Extract each section records
     * (arranged from "int ia64_log_platform_info_print()")
     */
    for (ercd_pos = sizeof(sal_log_record_header_t), sects = 0;
        ercd_pos < record_len; ercd_pos += sp->len, sects++) {
        sp = (sal_log_section_hdr_t *)((char*)buffer + ercd_pos);
        if (!efi_guidcmp(sp->guid, SAL_PROC_DEV_ERR_SECT_GUID)) {
            LOG_INDEX_ADD_SECT_PTR(slidx->proc_err, sp);
        } else if (!efi_guidcmp(sp->guid,
                SAL_PLAT_MEM_DEV_ERR_SECT_GUID)) {
            platform_err = 1;
            LOG_INDEX_ADD_SECT_PTR(slidx->mem_dev_err, sp);
        } else if (!efi_guidcmp(sp->guid,
                SAL_PLAT_SEL_DEV_ERR_SECT_GUID)) {
            platform_err = 1;
            LOG_INDEX_ADD_SECT_PTR(slidx->sel_dev_err, sp);
        } else if (!efi_guidcmp(sp->guid,
                SAL_PLAT_PCI_BUS_ERR_SECT_GUID)) {
            platform_err = 1;
            LOG_INDEX_ADD_SECT_PTR(slidx->pci_bus_err, sp);
        } else if (!efi_guidcmp(sp->guid,
                SAL_PLAT_SMBIOS_DEV_ERR_SECT_GUID)) {
            platform_err = 1;
            LOG_INDEX_ADD_SECT_PTR(slidx->smbios_dev_err, sp);
        } else if (!efi_guidcmp(sp->guid,
                SAL_PLAT_PCI_COMP_ERR_SECT_GUID)) {
            platform_err = 1;
            LOG_INDEX_ADD_SECT_PTR(slidx->pci_comp_err, sp);
        } else if (!efi_guidcmp(sp->guid,
                SAL_PLAT_SPECIFIC_ERR_SECT_GUID)) {
            platform_err = 1;
            LOG_INDEX_ADD_SECT_PTR(slidx->plat_specific_err, sp);
        } else if (!efi_guidcmp(sp->guid,
                SAL_PLAT_HOST_CTLR_ERR_SECT_GUID)) {
            platform_err = 1;
            LOG_INDEX_ADD_SECT_PTR(slidx->host_ctlr_err, sp);
        } else if (!efi_guidcmp(sp->guid,
                SAL_PLAT_BUS_ERR_SECT_GUID)) {
            platform_err = 1;
            LOG_INDEX_ADD_SECT_PTR(slidx->plat_bus_err, sp);
        } else {
            LOG_INDEX_ADD_SECT_PTR(slidx->unsupported, sp);
        }
    }
    slidx->n_sections = sects;

    return platform_err;
}

static int
init_record_index_pools(void)
{
    int i;
    int rec_max_size;  /* Maximum size of SAL error records */
    int sect_min_size; /* Minimum size of SAL error sections */
    /* minimum size table of each section */
    static int sal_log_sect_min_sizes[] = {
        sizeof(sal_log_processor_info_t)
        + sizeof(sal_processor_static_info_t),
        sizeof(sal_log_mem_dev_err_info_t),
        sizeof(sal_log_sel_dev_err_info_t),
        sizeof(sal_log_pci_bus_err_info_t),
        sizeof(sal_log_smbios_dev_err_info_t),
        sizeof(sal_log_pci_comp_err_info_t),
        sizeof(sal_log_plat_specific_err_info_t),
        sizeof(sal_log_host_ctlr_err_info_t),
        sizeof(sal_log_plat_bus_err_info_t),
    };

    /*
     * MCA handler cannot allocate new memory on flight,
     * so we preallocate enough memory to handle a SAL record.
     *
     * Initialize a handling set of slidx_pool:
     *   1. Pick up the max size of SAL error records
     *   2. Pick up the min size of SAL error sections
     *   3. Allocate the pool as enough to 2 SAL records
     *     (now we can estimate the maxinum of section in a record.)
     */

    /* - 1 - */
    rec_max_size = sal_rec_max;

    /* - 2 - */
    sect_min_size = sal_log_sect_min_sizes[0];
    for (i = 1; i < sizeof sal_log_sect_min_sizes/sizeof(size_t); i++)
        if (sect_min_size > sal_log_sect_min_sizes[i])
            sect_min_size = sal_log_sect_min_sizes[i];

    /* - 3 - */
    slidx_pool.max_idx = (rec_max_size/sect_min_size) * 2 + 1;
    slidx_pool.buffer = (slidx_list_t *)
        kmalloc(slidx_pool.max_idx * sizeof(slidx_list_t), GFP_KERNEL);

    return slidx_pool.buffer ? 0 : -ENOMEM;
}


/*****************************************************************************
 * Recovery functions                                                        *
 *****************************************************************************/

static mca_type_t
is_mca_global(peidx_table_t *peidx, pal_bus_check_info_t *pbci,
          struct ia64_sal_os_state *sos)
{
    pal_processor_state_info_t *psp =
        (pal_processor_state_info_t*)peidx_psp(peidx);

    /*
     * PAL can request a rendezvous, if the MCA has a global scope.
     * If "rz_always" flag is set, SAL requests MCA rendezvous
     * in spite of global MCA.
     * Therefore it is local MCA when rendezvous has not been requested.
     * Failed to rendezvous, the system must be down.
     */
    switch (sos->rv_rc) {
        case -1: /* SAL rendezvous unsuccessful */
            return MCA_IS_GLOBAL;
        case  0: /* SAL rendezvous not required */
            return MCA_IS_LOCAL;
        case  1: /* SAL rendezvous successful int */
        case  2: /* SAL rendezvous successful int with init */
        default:
            break;
    }

    /*
     * If One or more Cache/TLB/Reg_File/Uarch_Check is here,
     * it would be a local MCA. (i.e. processor internal error)
     */
    if (psp->tc || psp->cc || psp->rc || psp->uc)
        return MCA_IS_LOCAL;
    
    /*
     * Bus_Check structure with Bus_Check.ib (internal bus error) flag set
     * would be a global MCA. (e.g. a system bus address parity error)
     */
    if (!pbci || pbci->ib)
        return MCA_IS_GLOBAL;

    /*
     * Bus_Check structure with Bus_Check.eb (external bus error) flag set
     * could be either a local MCA or a global MCA.
     *
     * Referring Bus_Check.bsi:
     *   0: Unknown/unclassified
     *   1: BERR#
     *   2: BINIT#
     *   3: Hard Fail
     * (FIXME: Are these SGI specific or generic bsi values?)
     */
    if (pbci->eb)
        switch (pbci->bsi) {
            case 0:
                /* e.g. a load from poisoned memory */
                return MCA_IS_LOCAL;
            case 1:
            case 2:
            case 3:
                return MCA_IS_GLOBAL;
        }

    return MCA_IS_GLOBAL;
}

static u64
get_target_identifier(peidx_table_t *peidx)
{
    u64 target_address = 0;
    sal_log_mod_error_info_t *smei;
    pal_cache_check_info_t *pcci;
    int i, level = 9;

    /*
     * Look through the cache checks for a valid target identifier
     * If more than one valid target identifier, return the one
     * with the lowest cache level.
     */
    for (i = 0; i < peidx_cache_check_num(peidx); i++) {
        smei = (sal_log_mod_error_info_t *)peidx_cache_check(peidx, i);
        if (smei->valid.target_identifier && smei->target_identifier) {
            pcci = (pal_cache_check_info_t *)&(smei->check_info);
            if (!target_address || (pcci->level < level)) {
                target_address = smei->target_identifier;
                level = pcci->level;
                continue;
            }
        }
    }
    if (target_address)
        return target_address;

    /*
     * Look at the bus check for a valid target identifier
     */
    smei = peidx_bus_check(peidx, 0);
    if (smei && smei->valid.target_identifier)
        return smei->target_identifier;

    return 0;
}

static int
recover_from_read_error(slidx_table_t *slidx,
            peidx_table_t *peidx, pal_bus_check_info_t *pbci,
            struct ia64_sal_os_state *sos)
{
    u64 target_identifier;
    pal_min_state_area_t *pmsa;
    struct ia64_psr *psr1, *psr2;
    ia64_fptr_t *mca_hdlr_bh = (ia64_fptr_t*)mca_handler_bhhook;

    /* Is target address valid? */
    target_identifier = get_target_identifier(peidx);
    if (!target_identifier)
        return fatal_mca("target address not valid");

    /*
     * cpu read or memory-mapped io read
     *
     *    offending process  affected process  OS MCA do
     *     kernel mode        kernel mode       down system
     *     kernel mode        user   mode       kill the process
     *     user   mode        kernel mode       down system (*)
     *     user   mode        user   mode       kill the process
     *
     * (*) You could terminate offending user-mode process
     *    if (pbci->pv && pbci->pl != 0) *and* if you sure
     *    the process not have any locks of kernel.
     */

    /* Is minstate valid? */
    if (!peidx_bottom(peidx) || !(peidx_bottom(peidx)->valid.minstate))
        return fatal_mca("minstate not valid");
    psr1 =(struct ia64_psr *)&(peidx_minstate_area(peidx)->pmsa_ipsr);
    psr2 =(struct ia64_psr *)&(peidx_minstate_area(peidx)->pmsa_xpsr);

    /*
     *  Check the privilege level of interrupted context.
     *   If it is user-mode, then terminate affected process.
     */

    pmsa = sos->pal_min_state;
    if (psr1->cpl != 0 ||
       ((psr2->cpl != 0) && mca_recover_range(pmsa->pmsa_iip))) {
        /*
         *  setup for resume to bottom half of MCA,
         * "mca_handler_bhhook"
         */
        /* pass to bhhook as argument (gr8, ...) */
        pmsa->pmsa_gr[8-1] = target_identifier;
        pmsa->pmsa_gr[9-1] = pmsa->pmsa_iip;
        pmsa->pmsa_gr[10-1] = pmsa->pmsa_ipsr;
        /* set interrupted return address (but no use) */
        pmsa->pmsa_br0 = pmsa->pmsa_iip;
        /* change resume address to bottom half */
        pmsa->pmsa_iip = mca_hdlr_bh->fp;
        pmsa->pmsa_gr[1-1] = mca_hdlr_bh->gp;
        /* set cpl with kernel mode */
        psr2 = (struct ia64_psr *)&pmsa->pmsa_ipsr;
        psr2->cpl = 0;
        psr2->ri  = 0;
        psr2->bn  = 1;
        psr2->i  = 0;

        return mca_recovered("user memory corruption. "
                "kill affected process - recovered.");
    }

    return fatal_mca("kernel context not recovered, iip 0x%lx\n",
             pmsa->pmsa_iip);
}

static int
recover_from_platform_error(slidx_table_t *slidx, peidx_table_t *peidx,
                pal_bus_check_info_t *pbci,
                struct ia64_sal_os_state *sos)
{
    int status = 0;
    pal_processor_state_info_t *psp =
        (pal_processor_state_info_t*)peidx_psp(peidx);

    if (psp->bc && pbci->eb && pbci->bsi == 0) {
        switch(pbci->type) {
        case 1: /* partial read */
        case 3: /* full line(cpu) read */
        case 9: /* I/O space read */
            status = recover_from_read_error(slidx, peidx, pbci,
                             sos);
            break;
        case 0: /* unknown */
        case 2: /* partial write */
        case 4: /* full line write */
        case 5: /* implicit or explicit write-back operation */
        case 6: /* snoop probe */
        case 7: /* incoming or outgoing ptc.g */
        case 8: /* write coalescing transactions */
        case 10: /* I/O space write */
        case 11: /* inter-processor interrupt message(IPI) */
        case 12: /* interrupt acknowledge or
                external task priority cycle */
        default:
            break;
        }
    } else if (psp->cc && !psp->bc) {   /* Cache error */
        status = recover_from_read_error(slidx, peidx, pbci, sos);
    }

    return status;
}

/*
 * recover_from_tlb_check
 * @peidx:  pointer of index of processor error section
 *
 * Return value:
 *  1 on Success / 0 on Failure
 */
static int
recover_from_tlb_check(peidx_table_t *peidx)
{
    sal_log_mod_error_info_t *smei;
    pal_tlb_check_info_t *ptci;

    smei = (sal_log_mod_error_info_t *)peidx_tlb_check(peidx, 0);
    ptci = (pal_tlb_check_info_t *)&(smei->check_info);

    /*
     * Look for signature of a duplicate TLB DTC entry, which is
     * a SW bug and always fatal.
     */
    if (ptci->op == PAL_TLB_CHECK_OP_PURGE
        && !(ptci->itr || ptci->dtc || ptci->itc))
        return fatal_mca("Duplicate TLB entry");

    return mca_recovered("TLB check recovered");
}

static int
recover_from_processor_error(int platform, slidx_table_t *slidx,
                 peidx_table_t *peidx, pal_bus_check_info_t *pbci,
                 struct ia64_sal_os_state *sos)
{
    pal_processor_state_info_t *psp =
        (pal_processor_state_info_t*)peidx_psp(peidx);

    /*
     * Processor recovery status must key off of the PAL recovery
     * status in the Processor State Parameter.
     */

    /*
     * The machine check is corrected.
     */
    if (psp->cm == 1)
        return mca_recovered("machine check is already corrected.");

    /*
     * The error was not contained.  Software must be reset.
     */
    if (psp->us || psp->ci == 0)
        return fatal_mca("error not contained");

    /*
     * Look for recoverable TLB check
     */
    if (psp->tc && !(psp->cc || psp->bc || psp->rc || psp->uc))
        return recover_from_tlb_check(peidx);

    /*
     * The cache check and bus check bits have four possible states
     *   cc bc
     *    1  1  Memory error, attempt recovery
     *    1  0  Cache error, attempt recovery
     *    0  1  I/O error, attempt recovery
     *    0  0  Other error type, not recovered
     */
    if (psp->cc == 0 && (psp->bc == 0 || pbci == NULL))
        return fatal_mca("No cache or bus check");

    /*
     * Cannot handle more than one bus check.
     */
    if (peidx_bus_check_num(peidx) > 1)
        return fatal_mca("Too many bus checks");

    if (pbci->ib)
        return fatal_mca("Internal Bus error");
    if (pbci->eb && pbci->bsi > 0)
        return fatal_mca("External bus check fatal status");

    /*
     * This is a local MCA and estimated as a recoverable error.
     */
    if (platform)
        return recover_from_platform_error(slidx, peidx, pbci, sos);

    /*
     * On account of strange SAL error record, we cannot recover.
     */
    return fatal_mca("Strange SAL record");
}

static int
mca_try_to_recover(void *rec, struct ia64_sal_os_state *sos)
{
    int platform_err;
    int n_proc_err;
    slidx_table_t slidx;
    peidx_table_t peidx;
    pal_bus_check_info_t pbci;

    /* Make index of SAL error record */
    platform_err = mca_make_slidx(rec, &slidx);

    /* Count processor error sections */
    n_proc_err = slidx_count(&slidx, proc_err);

     /* Now, OS can recover when there is one processor error section */
    if (n_proc_err > 1)
        return fatal_mca("Too Many Errors");
    else if (n_proc_err == 0)
        /* Weird SAL record ... We can't do anything */
        return fatal_mca("Weird SAL record");

    /* Make index of processor error section */
    mca_make_peidx((sal_log_processor_info_t*)
        slidx_first_entry(&slidx.proc_err)->hdr, &peidx);

    /* Extract Processor BUS_CHECK[0] */
    *((u64*)&pbci) = peidx_check_info(&peidx, bus_check, 0);

    /* Check whether MCA is global or not */
    if (is_mca_global(&peidx, &pbci, sos))
        return fatal_mca("global MCA");
    
    /* Try to recover a processor error */
    return recover_from_processor_error(platform_err, &slidx, &peidx,
                        &pbci, sos);
}

/*
 * =============================================================================
 */

int __init mca_external_handler_init(void)
{
    if (init_record_index_pools())
        return -ENOMEM;

    /* register external mca handlers */
    if (ia64_reg_MCA_extension(mca_try_to_recover)) {   
        printk(KERN_ERR "ia64_reg_MCA_extension failed.\n");
        kfree(slidx_pool.buffer);
        return -EFAULT;
    }
    return 0;
}

void __exit mca_external_handler_exit(void)
{
    /* unregister external mca handlers */
    ia64_unreg_MCA_extension();
    kfree(slidx_pool.buffer);
}

module_init(mca_external_handler_init);
module_exit(mca_external_handler_exit);

module_param(sal_rec_max, int, 0644);
MODULE_PARM_DESC(sal_rec_max, "Max size of SAL error record");

MODULE_DESCRIPTION("ia64 platform dependent mca handler driver");
MODULE_LICENSE("GPL");